Optical Sheet Folds Prevent Thermal Bending and Contamination
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Solution Overview
Problem
Conventional liquid crystal display devices face issues with nonuniform light and foreign substance entry due to thermal expansion of the optical sheet, which can cause image deterioration.
Innovation Solution
The design incorporates a polygonal optical sheet with extension portions and curtain portions, both featuring folds, to prevent foreign substance entry and thermal expansion-induced bending, using a single sheet member to surround the optical member and accommodate the optical sheet, ensuring the optical sheet's flatness and preventing foreign substances from moving into the display region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a clearance space is secured between the optical sheet and the frame to avoid thermal expansion-induced bending, then the optical sheet's flatness is maintained, but foreign substances can enter the clearance space and move into the display region causing image deterioration
Solution Approach 1:
The optical sheet is divided into a body part and extension portions that extend beyond the body part's peripheral edges. The extension portions are placed between the optical member and the accommodating member, effectively segmenting the clearance space and preventing foreign substance entry while maintaining the optical sheet's flatness through the fold structure.
Solution Approach 2:
The extension portions act as an intermediary barrier between the clearance space and the display region. These portions, positioned between the optical member and accommodating member, prevent foreign substances from moving from the clearance space into the display region while allowing the optical sheet to accommodate thermal expansion.
2Area of stationary object
If the optical sheet is made larger to cover the optical member completely, then the optical effect is improved, but thermal expansion causes bending of the plate surface leading to nonuniform light
Solution Approach 1:
The optical sheet incorporates folds in the extension portions, allowing the sheet to dynamically adjust its shape in response to thermal expansion. The folds enable the extension portions to expand and contract without causing bending of the main body part, thus maintaining plate surface flatness while accommodating size changes.
Solution Approach 2:
The fold structure changes the physical parameters of the extension portions, allowing them to expand and contract in a controlled manner. This parameter change enables the optical sheet to accommodate thermal expansion while maintaining the flatness of the critical body part area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively inhibits the entry of foreign substances and maintains the optical sheet's flatness, preventing image deterioration and ensuring consistent light distribution.
Implementation Method 1
an optical sheet that imparts an optical effect to light emitted from the optical member
Implementation Method 2
an optical sheet that imparts an optical effect to light emitted from the optical member
Implementation Method 3
since an increase in operating temperature of the optical sheet leads to a thermal expansion of the optical sheet along a plate surface
Data Source
AI summary
A lighting device includes: a light source; a plate-like optical member on which light from the light source falls; an optical sheet that imparts an optical effect to light emitted from the optical member; and an accommodating member that surrounds outer peripheral edges of the optical member and outer peripheral edges of the optical sheet. The optical sheet has a body part having a polygonal shape, extension portions provided on side portions of the body part and placed between the outer peripheral edges of the optical member and the chassis, and curtain portions, provided in corner portions of the body part, each of which connects the extension portions provided on adjacent ones of the side portions, and the extension portions and the curtain portions are provided with folds, respectively.